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RE: [ACTION-78] What it means to define OWL-1.1-Full as a "delta" to OWL-1.0-Full

From: Michael Schneider <schneid@fzi.de>
Date: Mon, 18 Feb 2008 10:57:36 +0100
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A0750D3A@judith.fzi.de>
To: "Alan Ruttenberg" <alanruttenberg@gmail.com>
Cc: <public-owl-wg@w3.org>
Hi Alan!

Alan Ruttenberg wrote:

>Hi Michael,
>
>This is a nice explanation - I've added it to http://www.w3.org/2007/ 
>OWL/wiki/Different_Kinds_Of_Semantics

Thanks!

>I'll make a minor comment - the language of if/then rules and firing,  
>evokes the idea that the semantic conditions can be implemented by a  
>rule engine - but the conditions, such as "ICEXT(x), is a subset of  
>ICEXT(y)" are not the usual sorts of consequents one sees in such  
>systems - so the analogy might confusing a bit, in addition to the  
>benefit it brings in helping explain how the conditions work.

Feel free to make this comment! It's true that not all semantic conditions
"encode" rules. 

AFAICT, this can be compared to some degree with the semantics of OWL-DL:

   Axiom            | Condition  
   --------------------------------
   SubClassOf(C D)  | C^Ic SUBSET D^Ic

It looks to me that this is not so much different from an OWL-Full semantic
condition (IFF condition), approximately:

   IFF
       I( SubClassOf(C D) ) = true  # "I(.)" is interpretation function
   THEN
       I(C), I(D) in I(owl:Class)
     AND
       I(C) subset I(D)

And, in fact, there shouldn't be a big difference, since both semantics are
model-theoretic. The difference is more in "architecture" ("layered" or
"accumulative" for Full, vs. "direct" for DL). And of course the semantics
themself are different, because Full semantics has all the RDFS semantics
with it.

Btw.: I found out in the meanwhile that the very last statement I made in my
example is wrong: One get's the transitive triple with "if-then" RDFS
semantics, too, i.e. one does not need OWL-Full's iff-semantics for this.
But this is IMHO a minor bug. :)

Cheers,
Michael

>
>Regards,
>Alan
>
>On Feb 12, 2008, at 10:12 AM, Michael Schneider wrote:
>> == 4. An example of a semantic condition ==
>>
>> Here is an example for how the layered approach works. The  
>> semantics for
>> subclassing axioms in RDFS and OWL-Full is discussed by 
>looking at the
>> respective semantic conditions involved. The following semantic  
>> condition is
>> given in the RDFS semantics spec [4]:
>>
>>   (SC-SUBCLASS)
>>
>>   IF
>>       <x,y> is in IEXT(I(rdfs:subClassOf))
>>   THEN
>>       x and y are in IC
>>     AND
>>       ICEXT(x) is a subset of ICEXT(y)

--
Dipl.-Inform. Michael Schneider
FZI Forschungszentrum Informatik Karlsruhe
Abtl. Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: Michael.Schneider@fzi.de
Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555

FZI Forschungszentrum Informatik an der Universität Karlsruhe
Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
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Received on Monday, 18 February 2008 09:57:57 GMT

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